Also if were doing the whole spelljammer thing I would like it to be earth-like and not specifically earth. And speaking of magic:

[hider=My idea]
Magic awakens on Earth, triggers the 'Big Evil' to come blow it up, (which it does) Mankind flees to outer space with the help of magic, but the planet was literally the power source of magic. After the destruction of the (earth-like) planet, chunks of the planet are highly sought after because of the intense power they bestow. Ships run off chunks of mountains or granite or basalt or sea-water. Swords have clumps of grass or stone in the blade giving the wielder power. Geomancers work to preserve what few pieces of their destroyed planet they can save with religious fervor and unlock the magic within those pieces. The 'Big Evil' wants only to destroy-a monster of the void and nothingness.
[/hider]
Not saying I want to do that^ but it's where my brain went. I might even flesh that setting out for something else :)